What happened
The incident occurred during the initial climb phase of an experimental flight departing from Montgomery Regional Airport (MGM) in Alabama. Shortly after takeoff, the pilot reported that the left engine had failed and attempted to feather the propeller. The pilot then contacted Dannelly Tower to inform them of the intention to return to the airport.
Subsequently, the pilot reported that the right engine also lost thrust. However, the right propeller was not feathered because the pilot was uncertain whether the engine was still producing power. Consequently, a gear-up forced landing was executed on a four-lane highway.
The investigation
Post-accident inspection of the aircraft revealed that the right propeller was in the feathered position while the left propeller remained in low pitch. Analysis of the aircraft's weight and balance indicated it was approximately 400 pounds over the maximum gross weight limit.
The aircraft engines were fueled with alcohol under FAA approval for research and development purposes. Notably, three days prior to the accident, the aircraft had experienced power surges and made a precautionary landing. No problems were found at that time, and flight operations continued.
Findings
Mechanical testing showed that the engines were successfully test-run after the incident. There has been no determination as to the cause of the reported engine failures. The aircraft was significantly overweight, which likely contributed to the inability to maintain altitude following the power loss.